Bulletin of the American Physical Society
Joint Fall 2011 Meeting of the Texas Sections of the APS, AAPT, and Zone 13 of the SPS
Volume 56, Number 7
Thursday–Saturday, October 6–8, 2011; Commerce, Texas
Session F6: Astronomy, Astrophysics and Space Station II |
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Chair: Kent Montgomery, Texas A&M University--Commerce Room: Science Building 122 |
Friday, October 7, 2011 3:40PM - 3:52PM |
F6.00001: Status and Prospects for the SuperCDMS Experiment Bedile Karabuga SuperCDMS, the successor of the Crygenic Dark Matter Search (CDMS), is a direct detection experiment operated near 40 mK to search for the generic class of dark matter candidates, Weakly Interacting Massive Particles (WIMPs). It is designed to search for the scattering of WIMPs with nuclei in terrestrial Ge detectors. To increase the discrimination power to select WIMP events (nuclear recoils) from the background events (electron recoils), and the resulting sensitivity of the experiment, SuperCDMS has developed an improved detector technology and produced interleaved Z-sensitive Ionization and Phonon (iZIP) detectors. In this talk I will describe the experiment and the performance of the iZIP detectors. [Preview Abstract] |
Friday, October 7, 2011 3:52PM - 4:04PM |
F6.00002: The effect of white non-stationary data on drifting signal detection Mauricio Flores, Alexander Stroeer, Matthew Benacquista We analyze the effect of non-stationary noise in the detection of drifting signals on unevenly sampled data. Initial frequency estimation is obtained from a Lomb-Scargle periodogram; which is followed by a global multi-start optimization, as working on a dense local Nelder-Mead iterator for parameter estimates. It has been found that a varying white noise level has no effect on the required relative signal-to-noise ratio for detection in the proposed algorithm, though affecting the absolute amplitude strength of the signal recording. Future work includes the addition of colored noise to this analysis. [Preview Abstract] |
Friday, October 7, 2011 4:04PM - 4:16PM |
F6.00003: Self-Calibration Technique for 3-point Intrinsic Alignment Correlations in Weak Gravitational Lensing Surveys Michael Troxel, Mustapha Ishak Weak gravitational lensing can be used to constrain cosmological parameters to high precision using the 2- and 3-point weak lensing shear correlations. The intrinsic alignment (IA) of galaxies has been shown to be a significant barrier to precision weak lensing measurements. We review a proposed self-calibration technique to calculate the induced gravitational lensing-galaxy intrinsic alignment correlation (GI) for the power spectrum in weak gravitational lensing surveys with photometric redshift measurements, which is expected to reduce the IA contamination by at least a factor of 10 for currently proposed surveys. We confirm this using an independent analysis and propose an expansion to the self-calibration technique for the weak lensing bispectrum in order to calculate the dominant lensing-lensing-intrinsic alignment correlation (GGI). We explore the performance of the GGI self-calibration technique and show that it can potentially reduce the IA contamination by up to a factor of 5-10 for most redshift bin choices. The self-calibration thus promises to be an efficient technique to remove both the 2-point and 3-point intrinsic alignment contamination from weak gravitational lensing measurements. [Preview Abstract] |
Friday, October 7, 2011 4:16PM - 4:28PM |
F6.00004: Magnetic reconnection during northward interplanetary magnetic field during the Whole Heliosphere Interval Shree Bhattarai, Ramon Lopez, Robert Bruntz, Kevin Pham, Yue Deng, Yanshi Huang The Whole Heliosphere Interval (WHI) occurred from March 20 (DOY 80) to April 17 (DOY 107) of 2008. We used Lyon-Fedder-Mobarry (LFM) simulation to simulate the geospace response to the solar wind input throughout the WHI using real solar wind conditions and studied the variation of magnetic reconnection with changing interplanetary magnetic field (IMF). Magnetic reconnection is the process in which the geomagnetic field interconnects with the IMF causing transfer of energy from the solar wind to the geospace. We will present results showing behavior of the reconnection potential when the IMF is northward and discuss limitations in current formulations of the dayside reconnection rate for northward IMF. [Preview Abstract] |
Friday, October 7, 2011 4:28PM - 4:40PM |
F6.00005: Controlling calibration errors in gravitational-wave detectors by precise location of calibration forces Hernan Daveloza, Mahmuda Afrin Badhan, Mario Diaz, Keita Kawabe, Pablo Konverski, Michael Landry, Richard Savage To optimize the scientific benefit of interferometric GW detectors, calibration accuracies of better than $5\%$ will be required. However, calibration forces applied to the test masses cause elastic deformation that is sensed by the interferometer detectors, inducing errors in the calibration. These errors increase with actuation frequency and can be greater than $50\%$ at frequencies above a few $kHz$ depending on the location of the calibration forces. They can be reduced significantly, to below $1\%$, by changing the position at which the forces are applied. Our finite- element modeling indicates that with the two forces located within $\pm 1mm$ of their design locations, calibration errors due to test mass elastic deformation can be kept below $1\%$ for frequencies up to $3.5kHz$. Thus, precise control of the location of calibration forces should enable overall calibration accuracies of better than $5\%$. [Preview Abstract] |
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